Grade 10 Science Reviewer -2nd Quarter Cheat Sheet

EM Waves are distur­bances that propagate through space and matter, transf­erring energy. They are produced by the vibration or accele­ration of charged particles.
Nature: They are transverse waves (vibra­tions are perpen­dicular to the direction of wave travel) and are non-me­cha­nical (don't require a medium, can travel in a vacuum).
Speed: All EM waves travel at the same speed in a vacuum: the Speed of Light (c = approx. 3.0 x 10⁸ m/s.

Electric Field (E) and Magnetic Field (B) are perpen­dicular to each other and to the direction of wave propag­ation.

Law of Reflection
1. The incident ray, the reflected ray, and the normal (a line perpen­dicular to the surface at the point of incidence) all lie in the same plane.
2. The angle of incidence (Angle i) is equal to the angle of reflection (Angle r).

Location: distance from mirror to image is equal to distance from mirror to object.
Orient­ation: always upright
Size: same size as the object
Type: always virtual

- Image formed in a plane mirror is Laterally Inverted - left and right are switched.


Multiple Reflec­tions

To calculate the number of images that are formed we place the plane mirrors tilted at an angle to each other, using the formula:

N = (360/angle) - 1

where: N is the number of images formed.

If the mirrors are parallel (facing each other), they form an infinite number of images.

Center of Curvature (C): center of the sphere from which the mirror section is taken.
Focus or Focal Point (F): point where parallel rays converge (concave) or appear to diverge from (convex).
Principal Axis: the line passing through C and F.
Vertex E (V/E): the center of the mirror.
Focal Length (f): distance from F to the vertex E.

A curved mirror is a reflecting surface in which the reflective surface is a section of sphere. There are two kinds of curved mirrors, the concave and the convex mirrors. A spoon is a kind of a curved mirror with both concave and convex mirror.